A219038 Numbers k such that 3^k - 14 is prime.

3, 4, 5, 8, 17, 19, 29, 124, 304, 640, 1205, 1549, 1805, 2492, 2945, 13075, 20237, 102763, 173755, 173828, 174040

Offset

1,1

Comments

a(22) > 2*10^5. - Robert Price, Aug 31 2013

Links

Table of n, a(n) for n=1..21.

Mathematica

Do[If[PrimeQ[3^n - 14], Print[n]], {n, 3, 3000}]
Select[Range[1000], PrimeQ[3^# - 14] &] (* Alonso del Arte, Nov 10 2012 *)

Prog

(PARI) is(n)=isprime(3^n-14) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Cf. Sequences of numbers k such that 3^k + m is prime:

(m = 2) A051783, (m = -2) A014224, (m = 4) A058958, (m = -4) A058959,

(m = 8) A217136, (m = -8) A217135, (m = 10) A217137, (m = -10) A217347,

(m = 14) A219035, (m = -14) A219038, (m = 16) A205647, (m = -16) A219039,

(m = 20) A219040, (m = -20) A219041, (m = 22) A219042, (m = -22) A219043,

(m = 26) A219044, (m = -26) A219045, (m = 28) A219046, (m = -28) A219047,

(m = 32) A219048, (m = -32) A219049, (m = 34) A219050, (m = -34) A219051. Note that if m is a multiple of 3, 3^k + m is also a multiple of 3 (for k greater than 0), and as such isn't prime.

Sequence in context: A216888 A362218 A106048 * A258454 A176776 A049931

Adjacent sequences: A219035 A219036 A219037 * A219039 A219040 A219041

Keyword

nonn,more

Author

Nicolas M. Perrault, Nov 10 2012

Extensions

a(16)-a(21) from Robert Price, Aug 31 2013

Status

approved